Gas-generating apparatus



' May 17-. 1927.

iii

Patented May 17, 1927.

res

means P 4. .1.11 i T GAS-GENERATIH G APPARLQKJUS.

-Appllcation filed January 17, 1923. Serial No.- 613,148.

My invention relates -to an improved method and apparatus for producing the various forins of artificial combustible gas from bituminous coal, now employed for industrial and domestic purposes.

Practically all of the present combustible gases of commerce, that are made from bituminous coal, are produced by either coking thecoal or by partial oxidatiomeither with air or steam or a mixture of the two. When air is employed the gas is called producer gas, and when steam alone is employed the gas is called water gas. \Vhen a mixture of air and steam is employed the gas is known as semi-water gas, and the gases made by coking a bituminous coal are usually known by the-term'coal gas.

In producer gas, as now manufactured, there is present a relatively large amount of nitrogen and the combustible consists almost entirely of carbon monoxide. In the semiwater gas, the nitrogen content is relatively lower than in the producer gas, and there is present, as a combustible element. in addition to carbon monoxide, some hydrogen. Theoretically, the water gas consists of a mixture of carbon monoxide and hydrogen.

From a theoretical standpoint, any solid carbonaceous fuel may be used in the production of any of the above mentioned gases, but in practice these gases are made from high grade coals because the methods and the various forms of apparatus employed have rendered the use of low grade fuels impractical for the reasonthat such low grade.

fuels introduce ditiiculties' of operation which have heretofore proven to be practically insurmountable.

It is well known that we have, throughout the world, numerous quantitiesot low grade fuels, as yet unmined, which have a fairly high calorific value, but which carry such arelati'vely large content of non-combustible material that it is not an economical proposition to transport. them to the present centers of use. and the relatively high ash or non-combustible content renders their use impractical in the present forms of'gas-producing apparatus. This situation favors the use, in the regions containing the deposits of relativelylow grade fuels, of methods and apparatus capable of utilizing such fuels in i. the-production of gases having a relatively high heating value, in order to make the transportation of such gases to the centers of use, an economical proposition.

his one of the objects of the present invention to provide a method and apparatus especially adapted for utilizing low grade fuels, and, while my invention might be em ployed close to the centers of use of the gas,

.poses thereby avoiding the production of smoke and the losses now incident to burnmg bituminous coal in ordinary furnaces. It is impossible to secure the maximum oilicieneyin the utilization of bituminous coals, by burning them, in a raw state, in ordinary furnaces because such use of these coals inevitably results in the production of a certain amount of smoke and the loss of the tar fuel.

- Also, the present methods of making coal gas produce large quantities of coke of a kind for which there is only a limited market so that the gas making plants have diflioulty in disposing of'the coke. By my invention I utilize the carbon which ordinarily forms the coke, to make combustible gas for which there is a ready market.

It isa further object of the invention to provide a method and apparatus by which the volatile matter contained in the coal may be collectedas by-products or may be utilized for ,the production of combustible gases. This double function is desirable under some conditions as it insures the complete utilization of the by-pro'ducts as well as the carbon of the coal, thus replacing by a single unit that is more etiicient and of less cost than present forms-of apparatus.

With the present. forms-of apparatus for making water gas it is generally understood that fuels containing a readily fusible ash are not suitable but I am able to utilize such fuels by my method and in my apparatus because of the relatively low temperature at which the operation is carried out.

P further object of my invention is to 'pro vide a method and apparatus by which the and other by products-which are more valucable for use in the chemical arts than as various desired forms of combustible gas may be produced, at will, from the same fuel.

I accomplish the foregoing objects of my invention by the method hereinafter described and with apparatus of which one form is illustrated in the accompanying drawing, this drawing being a side elevation of the apparatus with parts shown more or less diagrammatically and in section.

Referring to the drawing, it should be noted, at the outset, that the apparatus illustrated comprises a gas generator A that is externally heated by means of a combustible gas which may be produced in the generator itself or from a liquid fuel or from an indemay be replaced b any of the known forms of furnaces capa 1e of producing heating gases. I

. The generator A is of theup-draft type and the gases produced thereinare. with drawn from difl'erent portionsof the generator, as will be described more in detail hereinafter. Some of the gases produced in the generator A arepassed through a superheated B which is heated by the heating gases leaving-the chamber C which surrounds the generator A. The gases returning through the superheater Bare delivered into the bottom of the generator A and supply the heat that is necessary, incaddition to that sup plied by the heating gases in the chamber C. The surplus of gases produced in the. generator A are conducted through purifying apparatus to the-usual gas holder ,or the point of use. o

, The generator A is of upright cylindri cal form and near the bottom is tapered,

' as indicated at 10, this tapered portion being surroundedby the annular chamber C to the lower part of which the heating gases are delivered from the furnaces ,or burners 11. The furnaceslor burners 11 are supplied with combustible gases by the pipes 12 and with air by the pipes 13, it bein understood that the apparatusjust referred to for supplying the heatin gases to the chamber C may be replaced iiy any of the usual forms of furnaces for producing heatinggases. I have also shown, in connection with the furnaces or burners 11, supply pipes 14 for a liquid fuel which may be, used in starting the apparatus. The oil pipes 14 have control valves 14 therein and may be supplied, by a main 15, from any convenient sage to those in the other.

space 18 below the chamber C by means of ports 19. The space 18 ,is in direct communication with the space 20 surrounding the chamber 0 and formed between the outer wall 21 of the latter and the wall 22. The ports 17 as will be observed from the drawing, are so located as to be free fromob struction by ashes accumulating at the bottomof the generator and, in order to remove these ashes as they accumulate, suit:

the interior of the generator when the valve 25. at the lower end of the receiver, is open in order to discharge the ashes that have accumulated in the receiver.

The bed of fuel in the generator A may be from fifteen to twenty feet in depth and when the generator is in operation, the fuel will be practically exhausted of its volatile matter by the time it has descended lothe .levelof the lower end 26 of, the centrally arranged gas outlct'pipe 27. From this it will be understood that the generator is ordinarily filled with fuel to a height several feet above the lower cnd'of the pipe '27 and, for the purpose of supplying fuel to the chamber, any suitable form of charging apparatus may be used, and I have thus valve 31 will be closed and the valves 32 open.

The superheatcr B m'a consist of checkerwork arranged to provh e two sepcrate pas sages 33 and 34 for gases so that heat may be transferred from the gases in one pas- The heating gases from the chamber C are delivered, by

means of the outlet 35, to the passage 3:3

through the supcrheater B and from the latter through a stack 36 to the atmosphere.

The stack 36 is preferably jacketed to pro- Vide an annular chamber 37 which has communication, by means of the ports 38, with the passage 39 which, in turn, has communication with the passage 34 through the snperheater. p r

Arranged within the pipe 27 and spaced therefrom to provide an annular passage 40,

is a pipe 41 which extends to a considerable distance below the lower end of the pipe 27 and serves as an outlet for certain of the gases produced in the generator The pipe 41 leads, preferably, to a dust collector 42 which removes the dust from the gases in the usual manner, and the gases are withdrawn from the dust collector 42 through a pipe 43 to the intake side of a blower 44L which discharges them through a pipe 45 into the passage 39. In order to supp y gases to the burners or furnaces 11, I connect with .the pipe 43, a branch pipe 46 with whichthe open to the atmosphere, deliversairunder pressure to the pipe 50 with which the pipes 13 for supplying air to the burners or furnaces 11, are connected. Valves 51 are provided in the pipes 13for controlling the pas.- sage of air therethrough.

The blowers 44 and -48-may be operated from any suitable source of power and I have indicated these blowers as being driven respectively. bythe belts 52 and 53 front a power-drilven shaft 54, but it'will be understood that this arrangement of drive for the blowers is merelyfor purposes of illustration andthat any other preferred form of drive may be provided.

I provide in the pipe 41 a thermostaticallv-controlled valve, which is diagrammatically indicated at 55, and which is adapted to control the supply of steam from a'main 56 to a pipe 57 which discharges into the annular chamber 37, surrounding the stack 36, asindicated at 58. It will sometimes be desirable to supply additional quantities of steam to the apparatus, over and above that which will be supplied through the therinostatically-controlled valve 55, and for this purpose, I provide a direct connection between the main 56 and,

ammoniatherefrom and, for this purpose, I provide'a branch 61 from the pipe 27 which leads to a point beneath the surface of the water in the tar and ammonia collector 62. This. collector 62 is preferably jacketed, as indicafedat 63, and cooling water will be supplied to the jacket by means of the inlet and outlet pipes 64 and 65, respectively. A valve 66, at the bottom of the collector 62, operated by the floats 67, controls the discharge of the tars from the collector- 62. From the drawing it will be ob vious that when the level of thewater in the collector 62 rises,- the valve 66 will be opened and discharge a suflicient amount of contents of the collector to lower the level to a point which causes the floats 67, to close the valve 66. a

A discharge pipe 68 conducts the gases from the interior'o f the collector 62 to a Bil pipe 69 which has connection with the pipe 27 and which may also lead to a point of use or storage of the gases. Between the points of connection of the pipes 61 and 69, the pipe 27 is provided with a valve'i'l) 1 and beyond the point of connection of the pipe .69 the pipe 27 is provided witha valve- 71. A valve 7 2 is provided in the pipe 69.

A pipe 73 connects with the top of the generator A, as indicated at'74, and with the pipes 61 and has arrangedtherein a valve 75.

When the apparatus, justdescribed, is in operation, the coal in the generator, above the lower end of the pipe 27, is coked by the heat in the chamber C and also the heat from'the gases rising from the lower part of the generator, and either passing out through the pipe 27 or through the body of fuel surrounding this pipe, and the coal gas thus produced is drawn oil through the .pipe 73 and the pipe 62, intoLthe tar and ammonia collector 62, the head of water on the lower end of the pipe 61 sealing this pipe and also putting a back pressure on the generator. From the foregoii'ig it will be noted that theYcolting of" the fuel'surrounding the pipe 27 will be eifecf ed principally by the heat from the chamber C and from the. gases in the pipe 27. By the time the coal descends to the level of the lower endof the pipe 27, the volatile matter will have been completely driven oil and, from the level of the lower end of the pipe 27 to the level of the lower end of the pipe 41,

water gas will be produced which will be drawn otf'through the pipe 27. Some of thegases produced below the lower end of the pipe 41 will be drawn 'otl' throiigh thischamber C, the space 18 below the chamber C, theipassage 16 and the ports 17. The su-" perheated steam will be delivered to the pas:

: sage 39trom the annular chamber 3? surrounding the stack'to which steam will be supplied by the pipe 57. The mixture of superheated steam] and gases returning to the generator, as above described, will be heated up in the snperheater B by the gases escaping from the chamber tl and, on detherein,

livery to the interior of the generator, will supply to the fuel the heat required, in excess ()li tlltltsupplied from the chamber C,

1 to operate the generat,or,j the steam being decomposed andlorming water gas in the generator A, which will be drawn oil through the pipe 27., as previously described.

The valve 55 will be automatically controlled by the heat .of the gases escaping through the pipe 41, to control the supply of stc'amto the apparatus so that as the heat of the gases escaping through the pipe 41 rises above a predetermined degree more steam will be admitted to the apparatus which will react on the fuel in the generator and tend to reduce the heat of the fuel When the gases escaping through the pipe 41 are below a predetermined de gree the valve 55 will so restrictthe supply of steam as to permit an, increase in the temperature ot the fuelin thegenerator and in this way the temperature Will-be auto- }matically controlled by the supply of super- 1 heated steam.

- thus generated, to be returned through the p is tanaccumulation ofsinhcicnt pressure superheater B, to.the generator until there within the generator togbvercome the head of wateronjthe'lowerfend ot the pipe 61. When this. condition prevails the surplus of gas will escape through the collector 62, the valve 70 being closed and either the valve 71 or 72 being open. The-recirculation.of the gases through the generator as above described, results in a. rapidly rising temperature within the generator and when this temperature reaches a predetermined degree the valve wi'll be automatically actuated to supply steam to the apparatus and thereafter the apparatus will function in its normal manner. 1

The water gas discharged through the pipe 27 may be mixed with the coal gas drawn oil through the pipe 73,; by having the valve closed and the valve 75. open. The gases thus mixed in the pipe 61 Will superheater, the space 26 surrounding the pass through the tar and ammonia collector $2 and from there to 'thegpoint of use Under some circumstances it may be desired to avoid the production of tars and ammonia and this may be done by closing the valve 75 which will cause thegases in the upper part of "the generator to how downward to the lower end of the pipe 27 and, in passing throughthe hot fuel, the tars will be broken 'up and converted into combustible'gases; i i r The reaction that takes place in the lower.

part of the generator below the level o'fthe lower end ot the pipe ll, issubstantially to produce hydrogen and carbon dioxide with very little carbon monoxide, and this reaction takes place at a relatively low tom f perature Whichis below the usual tempera" ture at which the ash content of theituel is fused into large clinkers' Some of the gases produced in the part ot'the generator I below the level of the lower-end 'ot" the pipe 41, rises above this :level and pass through the hot zone of the generator andescape through the pipe 2?" In passing through this hot zone the carbon dioxide is broken down and carbon monoxide is formed.

According to my method thefuel is subjecfeLl to a relatively high teniperatureonly so long as, it contains a rela-tiyely large amount or carbon and when the,carbonin the fuel is exhausted to a pointwhich would permit the formation of clinkers, the temperature is reduced to a point below that I am thus able to operate the generatorcontinuously necessary to formthe clinkers.

without clinkers,

From the foregoing it will beseen that l have provided an extremely flexible method of producing fuel gases from bituminous coal which is adapted to produce coal and water gas simultaneously, or a mixture of the two, and in which itjis possible to utilize practically all of the volatile matters and carbon of the fuel.

the formation of troublesome Havinq thus described my invention, what I claim is:

In gas generating apparatus, the combination of a substantiallycylindrical gas generating chamber having a vertical. axis, means for externally heating said chamber means for supplying fuel to the upper part of said chamber, means for withdrawing gases from the upper part of said chamber,

a'plurality of concentric pipesextending longitudinally, through the upper part of said chamber and through which gases may be discharged, means for superheating the gases discharged through one of said pipes,

and means for returning such superheated gases to the lower part of the chamber.

In testimony whereof I 'atfix my signature.

LEO PAUL SEBILLE,

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